Certain semiconductor devices are known to generate excess heat during operation. This is especially true for power semiconductor devices, which are commonly utilized as switches or rectifiers in high-power electric circuits. Power inverters, for example, are deployed on electric and hybrid electric vehicles to provide three phase operating power to the vehicle's electric drive motor. Power inverters and other such devices must typically be cooled to ensure proper functioning. For this reason, the power modules housing such power devices are often provided with some form of cooling system. For example, conventional cooling systems commonly employ a cold plate (e.g., a heat sink) to transfer heat away from the power device. The heat sink may comprise a metal body (e.g., aluminum, copper, etc.) having a flat surface and a plurality of projections (“pin-fins”) extending away therefrom. The flat surface of the heat sink is placed in thermal contact with the power device (e.g. soldered to a substrate supporting the power device), and the pin-fins are exposed to a cooling source, typically air or a coolant liquid (e.g., glycol water). During device operation, heat is conducted away from the power device and into the pin-fins, which are convectively cooled by the cooling source.
Simple heat sink cooling systems of the type describe above achieve less than optimal power device cooling. The conductive heat transfer from the power device to the cold plate is generally less effective than direct contact cooling methods wherein a coolant fluid physically contacts the power device. Also, if coolant fluid is utilized, heat dissipation may be further reduced by coolant stagnation. These limitations may be mitigated by employing a direct contact active cooling system, which utilizes a pump to circulate the coolant fluid over or onto the power device. The most effective ones of these systems typically direct a dielectric coolant onto the electrical components (e.g., switches, diodes, etc.) proximate a top portion of the power device. However, direct contact active cooling systems are also limited in certain respects. Such cooling systems tend to be relatively complex and expensive to employ. In addition, such cooling systems are typically not self-contained and thus require multiple interconnections between components. This makes the mounting/interchanging of a power module employing such a cooling system more difficult and may also lead to coolant fluid contamination and leakage problems.
It should thus be appreciated that it would be desirable to provide a cooling system that is thermally efficient, is fully contained within a semiconductor module, avoids fluid contamination and leakage problems, and facilitates the mounting/interchanging of the module. It should further be appreciated that it would advantageous if such a cooling system is of a reduced complexity and is relatively inexpensive to manufacture. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.